The miniaturization of optical components is a frequent goal in the design of modern optical systems. For example, it is highly desirable to package telecommunications hardware into modules that fit into the bays found in electronic equipment racks. Since electronic bays are often thin rectangular slots, the modules fitting into the slots must be thin or “board-like” in shape. Optical components fitting into such a module must also be thin or narrow in one dimension.
Light emitted from an optical fiber expands into a cone of light characterized by a circular cross-sectional profile at any distance from the fiber end. Accommodating light having a circular cross-sectional profile requires lenses and other optical components that are not always compatible with thin modular geometry. Therefore, it is often necessary to convert light having a circular cross-sectional profile into light having a thin cross-sectional profile.
Cylindrical lenses have been used to convert the cross-sectional profile of light from circular to thin. These cylindrical lenses concentrate the optical power of a circular beam along a line of approximately the same width as the original beam, but with significantly reduced height. Although cylindrical lenses are able to concentrate a circular beam along a line, cylindrical lenses can be difficult and expensive to fabricate, especially at micro-dimensional sizes.
In view of the need for optical components with thin geometries, what is needed is a technique for changing the cross-sectional profile of a beam of light from circular to thin that is compatible with the thin geometries used in telecommunications systems and that is economical to fabricate.